A mass of

Answer choices

1. A

   Author Was Noncommittal8% picked this

   Masses of black water such as that observed last summer come into the bay more frequently than just

   The author allowed for the possibility that black water has come in the past two centuries, but she never committed to the idea that it has. So our author's argument is indifferent to the frequency at which black water comes. The author/argument only cares whether the episode of black water from a year ago was the most intense one of the past 200 years.

   8%
2. B

   Too Strong: every3% picked this

   Every species of coral in the bay was seriously harmed by the mass of black water that

   The author claimed that five species were wiped out. We don't know whether or not every species was harmed. We know at least five were. The author's argument doesn't hinge on 100% of coral being harmed. It is leaning purely on the idea that "if you wiped out coral that was more than 200 years old, then you're the strongest thing that has happened in the last 200 years".

   3%
3. C

   Too Strong3% picked this

   The mass of black water that swept through the bay last year did not decimate any plant or animal species

   Too Strong: "any" Out of Scope: "species that use coral" Opposite This is too strong. The author doesn't need to assume that the black water didn't decimate other stuff too. Not to mention, if we negate this and say that the black water also decimated stuff that makes use of coral, it would only make the black water seem more damaging / more intense, and thus it would just strengthen the author's conclusion.

   3%
4. D

   Correct83% picked this

   The mounds of centuries-old coral that were destroyed were not in especially fragile condition just before the black

   Why this is right

   If we negate this, we get a powerful objection that "the 200 year old coral was in an especially fragile condition just before the black water swept in". This suggests that last year's black water wasn't the strongest in two centuries, it was just the straw that broke the camel's back. Maybe a previous round of black water (or something else) had pummeled the coral so bad that the coral was almost wiped out, but barely held on. When we see an answer choice with "ruling out" language on Necessary Assumption, we should negate it (by removing the "not") to see if it becomes an objection.

   Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

   83%
5. E

   Opposite3% picked this

   Older specimens of coral in the bay were more vulnerable to damage from the influx of black water

   It wouldn't help the author if the older specimens were weaker / more vulnerable. The author is interpreting the wiping out of the older specimen (200+ years) as her primary evidence that this black water was the strongest in 200 years. If the older specimens were more vulnerable, then it's less impressive that last year's black water wiped out an older specimen.

   3%